Light extraction efficiency analysis of GaN-based LED with nanopatterned sapphire substrates

• Main Authors: Tsai, Pei-Jung, 蔡佩蓉
• Other Authors: Pan, Jui-Wen
• Format: Others
• Language: en_US
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/745ze6

碩士 === 國立交通大學 === 光電系統研究所 === 101 === In this paper we discuss the simulation of a nano-patterned sapphire substrates (NPSS) light emitting diode (LED) with two kind of optics software: wave optics software, Finite-Difference Time-Domain (FDTD) simulations, and the ray optics software, Light Tools (LTs) simulation. First, we find the trends and an optimal solution for the Light Extraction Efficiency (LEE) enhancement when the 2D-FDTD simulations are used to save on simulation time and computational memory. The rigorous coupled wave analysis (RCWA) method is utilized to evaluate the designs. The optimal solution is then applied in 3D-FDTD and LTs simulations. The results are similar and the difference in the LEE enhancement between the two simulations does not exceed 8.5% in the small LED chip area. More than 104 times computational memory is saved during the LTs simulation in comparison to the 3D-FDTD simulation. Moreover, the LEE enhancement from the side of the LED can be obtained in the LTs simulation. An actual size NPSS LED is simulated using the LTs. The results show a more than 307% improvement in the total LEE enhancement of the NPSS LED with the optimal solution compared to the conventional LED.